Double glazed light-transmitting panels constructed from a pair of plastic face sheets permanently bonded to and spaced by a metal grid core are well known in the prior art. Panels of this type are used in windows, walls, skylights and roofs. In the usual installation, the panels are fabricated with translucent plastic face sheets which allow natural light to enter a building. The double glaze construction with plastic face sheets also conserves energy because of the improved insulating characteristics of the panel.
The grid cores which support and space the face sheets are usually fabricated from metal elements, such as, I-beams and U-shaped channels in order to provide the requisite panel strength. The joining of plastic face sheets to metal grid core elements introduces serious delamination when the panel is subject to a broad range of temperature variations, or the temperature gradient is relatively large when measured from one face sheet to the other. This delamination is caused by the shearing action of the differential rare of thermal expansion of the two dissimilar materials employed, namely, the plastic used in the face sheets and the metal beams and channels used in the grid core.